Consolidated Condensed Statements Of Income - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Interest and dividend income:
Interest and fees on loans	$ 96,428,000	$ 77,787,000	$ 188,042,000	$ 150,203,000
Interest and dividends on:
Obligations of U.S. Government, its agencies and other securities	13,431,000	7,624,000	26,410,000	13,754,000
Interest Income, Securities, State and Municipal	2,906,000	2,676,000	5,818,000	5,123,000
Other interest income	1,909,000	260,000	5,305,000	413,000
Total interest and dividend income	114,674,000	88,347,000	225,575,000	169,493,000
Interest on deposits:
Demand and savings deposits	18,068,000	1,333,000	32,280,000	1,684,000
Time deposits	1,966,000	708,000	3,313,000	1,428,000
Interest on borrowings:
Short-term borrowings	728,000	190,000	1,552,000	434,000
Long-term debt	2,340,000	2,177,000	4,660,000	4,322,000
Total interest expense	23,102,000	4,408,000	41,805,000	7,868,000
Net interest income	91,572,000	83,939,000	183,770,000	161,625,000
Provision for (recovery of) credit losses	2,492,000	2,991,000	2,675,000	(1,614,000)
Net interest income after provision for credit losses	89,080,000	80,948,000	181,095,000	163,239,000
Noninterest Income [Abstract]
Debit card fee income	6,830,000	6,731,000	13,287,000	12,857,000
Bank owned life insurance income	1,332,000	2,374,000	2,517,000	3,549,000
ATM Fees	553,000	583,000	1,086,000	1,115,000
Gains (Losses) on Sales of Other Real Estate	12,000	4,000	3,000	4,000
Real Estate Owned, Valuation Allowance, Valuation Increase	0	0	15,000	30,000
Loss (gain) on equity securities, net	25,000	709,000	(380,000)	3,062,000
Other components of net periodic benefit income	1,893,000	3,027,000	3,786,000	6,054,000
Other	874,000	1,403,000	2,039,000	4,126,000
Total other income	25,015,000	31,193,000	49,402,000	62,849,000
Other expense:
Salaries and employee benefits	33,649,000	31,052,000	68,520,000	61,573,000
Employee Benefits and Share-based Compensation	10,538,000	10,199,000	21,354,000	20,698,000
Occupancy expense	3,214,000	3,040,000	6,567,000	6,254,000
Furniture and equipment expense	3,103,000	2,934,000	6,349,000	5,871,000
Data processing fees	9,582,000	8,416,000	18,332,000	15,920,000
Professional fees and services	7,365,000	6,775,000	14,586,000	12,633,000
Marketing	1,239,000	1,019,000	2,558,000	2,336,000
Insurance	1,960,000	1,245,000	3,774,000	2,650,000
Communication	1,045,000	935,000	2,082,000	1,825,000
Excise and Sales Taxes	1,096,000	1,167,000	2,374,000	2,359,000
Amortization of Intangible Assets	328,000	403,000	655,000	805,000
Other expense	2,766,000	2,863,000	5,237,000	4,497,000
Total other expense	75,885,000	70,048,000	152,388,000	137,421,000
Income before income taxes	38,210,000	42,093,000	78,109,000	88,667,000
Income taxes	6,626,000	7,769,000	12,792,000	15,468,000
Net income	$ 31,584,000	$ 34,324,000	$ 65,317,000	$ 73,199,000
Net income available to common shareholders
Basic	$ 1.95	$ 2.11	$ 4.03	$ 4.51
Diluted	$ 1.94	$ 2.10	$ 4.01	$ 4.48
Weighted average common shares outstanding
Basic	16,165,119	16,249,307	16,203,736	16,234,598
Diluted	16,240,600	16,361,246	16,282,693	16,346,141
Quarterly Dividend
Weighted average common shares outstanding
Cash dividends declared	$ 1.05	$ 1.04	$ 2.10	$ 2.08
Fiduciary and Trust [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 8,816,000	$ 8,859,000	$ 17,431,000	$ 17,656,000
Deposit Account [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	2,041,000	2,563,000	4,282,000	4,637,000
Bank Servicing [Member]
Noninterest Income [Abstract]
Revenue from Contract with Customer, Including Assessed Tax	$ 2,639,000	$ 4,940,000	$ 5,336,000	$ 9,759,000